Chapter 7 Building robot with MicroCamp kit

Transcription

1 MicroCamp : ATmega8 Activity Kit Manual l 63 Chapter 7 Building robot with MicroCamp kit This chapter focus learning the applications of the MICROCAMP microcontroller. The building of a robot integrates knowledge and technology which includes electronics, programming, mechanical movements, and thinking process. The Microcamp Activity kit supports this concept. This kit includes all parts for building a simple mobile robot. Users can learn about programming and how to apply the microcontroller aspects via robotic activities. The Mobile robot in MICROCAMP has 2 DC Motor gearboxes for moving and 4 sensors for detecting external values. These are 2 touch sensors and 2 Infrared Reflector Line tracking sensors for use in black and white line following. Part list 48:1 DC motor gearbox x 2 Circle base plate MicroCamp board Box holder x 1 Wheel and Tire set x 2 Plastic spacer set x 1 Nut and Screw set x 1 Ploastic joiners (Straight, Right angle and Obtuse) Infrared reflector x 2 Swithc module x 2 2mm. Self-tapping screw x2 25mm. metal spacer x 2

2 64 l MicroCamp : ATmega8 Activity Kit Manual Construction 1. Fix on the 2 wheels with the rubber tires and attach them to the DC Gearbox with the 2 of the 2mm. self-tapping screws provided in the kit. 2. Install both the DC Gearboxes on the circular base plate at the specific positions shown in the picture with 4 of 3 x 6mm. machine screws. motor attached position 3. Insert the 3 x 10mm. machine screws through the hole at the corner of the Box holder with 25mm. and 2 of 3 mm. spacers. 25mm. metal spacer 2 of 3mm. plastic spacer Hole position for attached spacers 4. Place the Box holder from step 3 on the top of the Circle base plate and attach them with 3 x 10mm. screws at the specific positions. Hole position for attached box holder Hole position for attached box holder

3 MicroCamp : ATmega8 Activity Kit Manual l Insert a 3x15mm. machine screw through the Infrared Reflector sensor, followed by 2 of the 3mm. spacer. Do on both sides for this. 3 x 15mm. machine screw 3mm. spacer x 2 6. Attach both the Infrared Reflector structures from step 5 at the suitable holes at the bottom and front of the robot base. Tighten with a 3mm. nut. Hole position for attached Infrared Reflector sensor 7. Observe the distance from the floor to the sensors. The suitable distance is 3 to 5 mm. Distance is 3 to 5 mm. 8. Place MicroCamp board on the box holder. Connect sensor cables and motor cables following the diagrams shown. (P0 for Right sensor and P1 for Left sensor). Black Red Right sensor cable Black Left sensor cable Red Motor connection Infrared Reflector sensor connection

4 66 l MicroCamp : ATmega8 Activity Kit Manual 9. Attach the Straight joiner with robot base at front-right side by 3 x 10mm. machine screw and 3mm. nut. Attach 2 pieces. 10. Connect the Obtuse joiner at the end of Straight joiner. Attach the right angle joiner with Switch module by 3 x 10mm. machine screw and 3mm. nut. Make 2 sets. Bring these structures to connect at the end of the Obtuse joiner. Connect 2 sides. 11. Connect the Left Switch module cable to the P2 (PC2) connector and the Right Switch module cable to the P3 (PC3) connector. Put 4 AA batteries into battery holder at the back of MicroCamp board. The MicroCamp robot is ready for programming now.

5 MicroCamp : ATmega8 Activity Kit Manual l 67 Learning about the Switch circuit The switch that is used with the MicroCamp has the following schematic: +V Signal connector LED1 R1 510 R2 10k R3 220 DATA Indicator Switch S1 GND Pressing the switch results in two occurrences. When the switch is not pressed, let the results be logic 1 When the switch is pressed, let the results be logic 0, and LED1 light up. Since the switch can give two results, it is considered to be a digital input component. More information of Infrared Reflector Signal connector +V OUT TCRT5000 GND 10k 510 Infrared Reflector sensor The heart of this sensor circuit is the sensor that detects reflections from infrared light. It consists of the Infrared LED which emits infrared light to the surface. Photo-transistors will then receive the reflected infrared lights. If no infrared light is received, the OUT terminal will have low voltage when measured. In the case that it receives infrared light, whether low or high current passes through the photo-transistor depends on the intensity of the light received which in turn varies according to the distance of the reflection. (Sensor TCRT5000 can be used at a distance of centimeters). Therefore, 0.5 5V can be measured at the OUT terminal, and the MicroCamp will get a value of 30 to 1023.

6 68 l MicroCamp : ATmega8 Activity Kit Manual Activity 1 Basic movement of MicroCamp robot Activity 1-1 Forward and Backward movement A1.1 Open the AVR Studio to create the new project and write the C program following the Listing A1-1. Build this project. A1.2 Connect the PX-400 programmer to the MicroCamp board on The MicroCamp robot at the In-System Prog. connector. Turn-on the Robot. Downlaod the HEX code to the robot. A1.3 Turn-off power and Remove the ISP cable. A1.4 Make sure the robot is on a flat surface. Turn-on the power and observe the operation. The MicroCamp robot moves forward. See both LED motor indicators light in green color. After 1 second, both indicators change color to red and the robot moves backward. If this is incorrect you will need to re-connect the motor cable to its opposite port / polarity. Do this until your robot moves correctly. Once its done, Use this motor port configuration for all your programming activities from now on. The robot will move forward and backward continually until you turn off its power. #include <in_out.h> #include <sleep.h> #include <motor.h> // Motor driver library void main() // Endless loop forward(100); // Move the robot forward. sleep(1000); // Delays 1 second. backward(100); // Move the robot backward. sleep(1000); // Delays 1 second. Listing A1-1 The C Program that allows the Microcamp Robot to move in circles.

7 MicroCamp : ATmega8 Activity Kit Manual l 69 Activity 1-2 Circle-shape movement control A1.5 Create a new project file and write the following C Codes shown in A1-2. A1.6 Connect the PX-400 programmer to the MicroCamp board on The MicroCamp robot at the In-System Prog. connector. Turn-on the Robot. Downlaod the HEX code to the robot. A1.7 Turn-off power and Remove the ISP cable. A1.8 Make sure the robot is on a flat surface. Turn-on the power and observe the robot. The robot will be activated when you press SW1 and move in circles continually until you press the SW2 to stop the robot movement. #include <in_out.h> #include <sleep.h> #include <motor.h> void main() while((in_d(2)==1)); // Loop for checking SW1 pressed motor(1,100); // Apply full power for Motor 1 motor(2,30); // Apply 30% power for Motor 2 while((in_d(3)==1)); // Loop for checking if SW2 pressed motor_off(); // Stop all motors. Program description In Listing A1-2, the forward and backward com-- mands are not used for driving the robot. The MOTOR function is used instead. This function can control both motor outputs separately. This means that you can control both the motor s speed differently. When both speeds are not equal, the robot will move towards the direction where the motor is of a lower speed. If the speed difference is great, the MicroCamp robot will move in circles. The While command is used in this program. If SW1 at PD2 port is being pressed, the LOGIC value of O is returned. The first conditional loop is false. It then continues with the second conditional loop. If SW2 at PD3 port is press, the Program will stop both motors. The Robot will stop its movement. Listing A1-2 The C program for MicroCamp robot move circle shape activity.

8 70 l MicroCamp : ATmega8 Activity Kit Manual Activity 1-3 Square-shape movement control A1.9 Create a new project file and write the following C Codes shown in A1-3. Connect the PX-400 programmer box to the MicroCamp board on The MicroCamp robot at the In- System Prog. connector. Turn-on the Robot. Downlaod the HEX code to the robot. A1.10 Turn-off power and Remove the ISP cable. Make sure the robot is on a flat surface. Turn-on the power and observe the robot. The robot will be activated if SW1 or SW2 is being pressed. If you Press SW1, the robot will move forward and turn left continually, making a square. If you press SW2, the operation is vice versa. #include <in_out.h> #include <sleep.h> #include <motor.h> void main() if (in_d(2)==0) forward(100); sleep(900); s_right(50); sleep(300); if (in_d(3)==0) forward(100); sleep(900); s_left(50); sleep(300); // Looping // Check SW1 pressing // Move forward with full speed 0.9 second // Turn right with 50% speed 0.3 second // Check SW2 pressing // Move forward with full speed 0.9 second // Turn left with 50% speed 0.3 second Press SW2 (Move forward and Turn right) Press SW1 (Move forward and Turn left) Listing A1-3 The C Program for movement selection of the Microcamp Robot.

9 MicroCamp : ATmega8 Activity Kit Manual l 71 Activity 2 Object detection with Collision Activity 2-1 Simple collision detection This activity is program the robot to detect the collision of both switches at the front of the MicroCamp robot. After a collision is encountered, the robot will move backward and change the its direction of movement. A2.1 Create a new project file and write the following C Codes shown in A1-4. Build this project. A2.2 Connect the PX-400 programmer box to the MicroCamp board on The MicroCamp robot at the In-System Prog. connector. Turn-on the Robot. A2.3 Download the HEX code to the robot. A2.4 Turn-off power and Remove the ISP cable. A2.6 Prepare the demonstration area by placing and securing boxes or objects on the surface. A2.7 Bring the robot into the demonstration area.turn-on the power and observe the robot. The MicroCamp robot will read both switch status from PD2 and PC3 port. If any switch is pressed or touches some object, the result is logic 0. In a normal operation, the robot will move forward continually. If the Left Switch module touches any object, the robot will move backward and change its moving direction to its right to avoid the object. If the Right Switch module touches any object, the robot will move backward and change its moving direction to its left to avoid the object.

10 72 l MicroCamp : ATmega8 Activity Kit Manual #include <in_out.h> #include <sleep.h> #include <motor.h> void main() while((in_d(2)==1)); if (in_c(2)==0) backward(100); // Loop until SW1 is pressed to start the program. // Repeat loop // Check status of the right switch. // If ther is a collision, the robot moves backward // for 0.4 second sleep(400); s_left(50); // and turns left for 0.3 second. sleep(300); else if (in_c(3)==0) // Check status of the left switch. backward(100); sleep(400); s_right(50); sleep(300); else forward(100); // If ther is a collision, the robot moves backward // for 0.4 second // and turns right 0.3 second. // No collision is deteced, // the robot moves forward continually. Robot attacks the object in the left. Robot attacks the object in the right. Listing A2-1 The C Program for Object Collision detection

11 MicroCamp : ATmega8 Activity Kit Manual l 73 Activity 2-2 Trapped in a corner situation When the Robot is in a corner, it is caught in between whereby to the left or right is a wall. This causes continous hitting of the walls and thus trapping the robot in this corner. The solution is to modify your exiting C Code from A2-1 to that which is shown in A2-2. A2.8 Create a new project file for making the C program according to Listing A2-2. A2.9 Connect the PX-400 programmer box to the MicroCamp board on The MicroCamp robot at the In-System Prog. connector. Turn-on the Robot. A2.10 Prepare the demonstration area by placing and securing boxes or objects on the surface. A2.11 Bring the robot into the demonstration area.turn-on the power and observe the robot. The robot will move forward and check for collision. If this happens over 5 times consecutively, the robot will spin 180 degrees to change its direction. #include <in_out.h> #include <sleep.h> #include <motor.h> #include <sound.h> void main() unsigned char cnt_=0; while((in_d(2)==1)); sound(3000,100); if (in_c(2)==0) if ((cnt_%2)==0) // Sound library // Declare variable for counting the number of // collision both left and right. // Wait for SW1 is pressed to start operation // Beep at once // Looping // Check the right-side collision // Check the counter as even number or not. // If yes, means the previous collision is left- // side collision. // Increment the counter // If not left-side collision, // clear the counter // Move backward 0.4 second cnt_++; else cnt_=0; backward(100); sleep(400); // s_left(50); // Turn left if (cnt_>5) // Check the counter over 5 or not. sleep(700); // If over, turn left more 0.7 second. sound(3000,100); // Drive sound to piezo speaker cnt_=0; // Clear counter Listing A2-2 The C program for MicroCamp robot in Trapping wall solution activity (continue..)

12 74 l MicroCamp : ATmega8 Activity Kit Manual else // If counter is less than 5, sleep(300); // Set time value for turning to 0.3 second. else if (in_c(3)==0) // Check the leftt-side collision if ((cnt_%2)==1) // Counter is odd number or not. // If yes, the previous collision is right-side. cnt_++; // Increment counter else cnt_=0; // If not, clear counter backward(100); // Robot move backward for 0.4 second sleep(400); // s_right(50); // Turn right for 0.3 second sleep(300); // else // If not collision, move forward. forward(100); Listing A2-2 The C program for MicroCamp robot in Trapping wall solution activity (final)

13 MicroCamp : ATmega8 Activity Kit Manual l 75 Activity 3 Line tracking robot From the 2 first activities, these show how to read the digtal input signal and to get the data to control robot movement. In this activity, there will be many activities about reading analog inputs and processing the data to detect black and white areas. It also detects Black and white line to control the robot to move along the line with conditions. The MicroCamp robot has 5 analog inputs that directly connects to the PC0 to PC4 of ATmega8 microcontroller. This microcontroller contains the 10-bit analog to digital converter (ADC) module. The digital conversion data is 0 to 1023 in decimal number format. C programming for this activity require a library file. It is the analog.h file. Functions in this library will define relate the input port to the analog input and reads data from ADC module to store in its memory. The resulting data range is 0 to 1023 in decimals or 0000H to 03FFH in hexadecimals. The important devices in this activity is the 2 Infrared Reflector modules. They are installed at the bottom of the robot base. They are used to detect the surface s color (black and white) including the white and black line. The Line tracking robot activity is the classic activity. It shows the basic robot s programming performance. Activity 3-1 Testing black and white area The MicroCamp robot is attached with 2 of Infrared Reflector module at bottom of the robot base ready. Thus, this activity will only dwell on programming. Before develop the robot to track the line, developers must program the robot to detect the difference between black and white color surface. (A) White surface testing This sub-activity presents how to detect the white surface. The Listing A3-1 is C program for testing Infrared Reflector operation. After execution, the program will wait for SW1 or SW2 pressing. If press SW1 : select to read data from P0 or PC0 analog port If press SW2 : select to read data from P1 or PC1 analog port After pressing the switch, the program will read data at the port pin continuously and will not switch to read another sensor unless the RESET button is pressed. Developers must press both switches to get the sensor s data.

14 76 l MicroCamp : ATmega8 Activity Kit Manual #include <in_out.h> #include <sound.h> #include <analog.h> void main() if((in_d(2)==0)) if (analog(0)>350) sound(3000,100); if((in_d(3)==0)) if (analog(1)>350) sound(3000,100); // Analog reading library // Loop for waiting the key selection to // read P0 or P1 // Check SW1 pressing // Repeat this loop // Read the value from P0 and check the // white surface. // If the white surface is deteced, // drive the sound to speaker. // Check SW2 pressing // Repeat this loop // Read the value from P1 and check the // white surface. // If the white surface is deteced, // drive the sound to speaker. Listing A3-1 The C program for MicroCamp robot in White surface testing activity Compare the sensor s data with the reference data; 350. If data values are more than 350, the color that is detected is white color. If data values are less than 350, the color that is detected is black color. After detect the white surface ready, program will send the sound signal to piezo speaker. A3.1 Make the black & white testing sheet. The white surface area is 30 x 30 cm. and black surface is 30 x 30cm. A3.2 Create the new project file and make the C program following the Listing A3-1. Build this project file. A3.3 Connect the PX-400 programmer box with MicroCamp robot and download the HEX code to the robot.

15 MicroCamp : ATmega8 Activity Kit Manual l 77 A3.4 Place the robot on the black surface first. Turn on the power and press SW1 switch. The Robot does not move. A3.5 Place the robot on the white surface and try to roll the robot. The robot produces sounds when its on a white surface. A3.6 Press the RESET switch. Place the robot on the black surface again. Press switch SW2 to test the operation of the Infrared Reflector at P1 port. Observe the robot s operation. After press SW2, robot will get data from sensors at P1 port and compare the reference value ; 350. If the reading value more than 350, means the robot detects the white area. It send sound signal to drive a piezo speaker. From step A3.6, robot detects the black surface then do not work anything. A3.7 Place the robot on the white surface and try to roll the robot. Robot drives sound always above the white surface. A3.8 If the robot cannot drive the signal when placed on the white surface in testing. The solution is (1) Decrease the reference value from 350 but not lower 100 (2) Adjust the sensor position to decrease the distance from the floor. A3.9 The Listing A3-2 is C program for testing the black surface. Developers can test with this program to check the black surface detection of robot to make sure the robot can detect white and black surface well. The procedure is same in step A3.4 to A3.8. But the decision criteria will change from higher 350 to lower 350 instead.

16 78 l MicroCamp : ATmega8 Activity Kit Manual #include <in_out.h> #include <sound.h> #include <analog.h> void main() P0 or P1 if((in_d(2)==0)) if (analog(0)<350) sound(3000,100); if((in_d(3)==0)) if (analog(1)<350) sound(3000,100); // Analog reading library // Loop for waiting key selection to read // Check SW1 pressing // Repeat this loop // Read the value from P0 and check the // black surface. // If the black surface is detected, // drive the sound to speaker. // Check SW2 pressing // Repeat the loop // Read the value from P1 and check the // black surface. // If the black surface is deteced, // drive the sound to speaker. Listing A3-2 The C program for MicroCamp robot check the Black surface activity

17 MicroCamp : ATmega8 Activity Kit Manual l 79 Activity 3-2 Robot moves along the black line The robot moving along the line has 3 scenarioes. (1) Both sensors read values that are white : The robot will move forward. Thus, this program is written so that the robot moves forward normally. (2) The left sensor reads black while the right sensor reads white : This occurs when the robot is slightly turned to the right. Thus, the program is written for the robot to move back left to resume its normal path. (3) The left sensor read white while the right sensor reads black : This occurs when the robot is slightly turned to the left. Thus, the program is written for the robot to move back to the right to resume its normal path. From all scenarioes, can make the C program in the Listing A3-3. Scenario-1 Both sensors put across Scenario-2 Left sensor detects the line Scenario-3 Right sensor detects the line A3.10 Make the simple black line sheet. It has not the cross line. Most area is white color. Size of sheet can determine suitable for your robot. A3.11 Create the new project file and make the C program following the Listing A3-3. Build this project file. A3.12 Connect the PX-400 programmer box with MicroCamp robot and download the HEX code to the robot. Turn off power and unplug ISP cable from the robot.

18 80 l MicroCamp : ATmega8 Activity Kit Manual #include <in_out.h> #include <sound.h> #include <analog.h> #include <motor.h> unsigned int AD0=350,AD1=350; void main() while((in_d(2)==1)); if((analog(0)>ad0)&&(analog(1)>ad1)) forward(100); if (analog(0)<ad0) s_left(100); if (analog(1)<ad1) s_right(100); // Motor diver library // Determine the sensor reference // value. // Wait pressing SW1 to start the // program // Both sensor detect the white // surface. // Move forward // Left sensor detects black line. // Turn left // Right sensor detects black line. // Turn right Listing A3-3 The C program for controlling the MicroCamp robot to moves along the black line A3.13 Place the robot across the black line on the sheet. Turn on power and press SW1 switch. Robot will move along the black line. It is possible that the robot moves out of the line. You can improve the precision by editing the program with adjusting the sensor reference value and adjust to the position of both the Infrared Reflector sensors.

19 MicroCamp : ATmega8 Activity Kit Manual l 81 Activity 3-3 Line crossing detection From the activity 3-2, you can improve the MicroCamp robot so that it moves along the black line and detect the junction or line with same 2 sensors. One thing to do is edit the program. When the robot moves to line crossing, both sensors will detect black line. You must add the program for support this scenario. The improved C program is shown in the Listing A3-4 A3.14 Improve the simple black line sheet from Activity 3-2. Add some cross lines. The number will depend on your inquiry. A3.15 Create the new project file and make the C program following the Listing A3-4. Build this project file. A3.16 Connect the PX-400 programmer box with MicroCamp robot and download the HEX code to the robot. Turn off power and unplug ISP cable from the robot. A3.17 Place the robot across the black line on the sheet. Turn on power and press SW1 switch. Robot will move along the black line. When the robot detects the crossing, it will brake and drive sound once. When it finds the second crossing, the robot will drive sound twice and this will increase for the subsequent crossings. Note : In the motor brake operation, robot will stop and lock the motor s shaft immediately. But sometimes, this is not enough. You must program the robot to move backwards for a short time. This will cause the robot to stop at its position.

20 82 l MicroCamp : ATmega8 Activity Kit Manual #include <in_out.h> #include <sound.h> #include <analog.h> #include <motor.h> unsigned int AD0=350,AD1=350; unsigned char i=0,j=0; void main() while((in_d(2)==1)); to // Motor control library // Sensor reference value // Crossing counter variable // Wait for SW1 to be pressed to // start if((analog(0)<ad0)&&(analog(1)<ad1)) // Detect line-crossing. j++; backward(30); // Move backward for a short time // to brake. sleep(10); motor_stop(all); // Motor brake function for (i=0;i<j;i++) // Repeat the loop // line-crossing detection sound(2500,100); sleep(50); // Drive sound forward(100); // Move forward to closs over sleep(300); // the line. if((analog(0)>ad0)&&(analog(1)>ad1)) // Both sensor detect white surface. forward(100); // Move forward if (analog(0)<ad0) // Left sensor detects black line. s_left(100); // Turn left if (analog(1)<ad1) // Right sensor detects black line. s_right(100); // Turn right Listing A3-4 The C program for controlling the MicroCamp robot to moves along the black line and detect the line-crossing.